Between 550,000 and 1.4 million people in West Africa could be infected with the Ebola virus by January 20, 2015, according to a worse case scenario study published by researchers at the US Centres for Disease Control and Prevention.

An outbreak of Ebola in West Africa has been largely contained in Senegal and Nigeria, the World Health Organisation (WHO) says, but the disease is still spreading elsewhere and has now killed over 2,811 people in the region.